On iPhone, go to Settings → Mobile Data → Add eSIM. If the option appears, your device is compatible. On Android, check Settings → Network & Internet → SIM. Many carriers also publish compatible device lists on their websites.
Can I use eSIM and a physical SIM at the same time?
Yes, on dual-SIM capable devices. You can use an eSIM for data on a budget carrier and a physical SIM for calls on another. Most recent iPhones and Pixel/Galaxy devices support this configuration. Note that only one line can be active for calls at a time.
Does eSIM support voice calls on budget carriers?
Many major budget carriers in Japan — including IIJmio, Rakuten Mobile, and ahamo — offer voice-capable eSIMs. Some smaller carriers offer data-only eSIMs. Always verify the plan includes voice service if you need it.